As a toxic and metalloid substance, excess arsenic (As) can cause serious harm to the environment and public health. In this work, crayfish shell biochar (CFS450) and modified biochar (MCFS450) were ...prepared to remove As(V) from aqueous solutions under various conditions. Compared to CFS450, MCFS450 had a higher specific surface area, better pore structure, and higher As(V) adsorption capacity. Based on the Langmuir model, its maximum As(V) adsorption capacity was 17.2 mg/g. The biochar had a large number of surface functional groups such as C-O, O-H, and -OH. After modification, a certain mass of ZnO nanoparticles existed on MCFS450, which increased positive charge on the surface and promoted the adsorption of As(V). As the temperature rose, the adsorption capacity increased, suggesting the adsorption was endothermic. Under low PH conditions, the adsorption effect was better. When Cl
−
, HCO
3
−
, SO
4
2−
, and PO
4
3−
respectively existed, the adsorption capacity decreased, indicating that As(V) competed with other anions. The column adsorption experiments showed that Thomas, Yoon-Nelson, and Adams-Bohart models can be expressed as a unified model (EXY model). The EXY model can be used for the design of biochar-based filter for As(V) removal, providing a theoretical basis for practical production applications.
Graphical abstract
Experimental setup and results of column adsorption.
In this study, crayfish shell was pyrolyzed at 600 °C to obtain an unmodified biochar (CS600). MgCl
2
was used as a modifier to pretreat crayfish shell to produce a modified biochar (CS600-MgCl
2
) ...under the same pyrolysis conditions. The two biochars were characterized for physicochemical properties and evaluated for lead (Pb
2+
) sorption ability to determine the modification mechanism. Mono-element batch adsorption experiments were conducted to compare the sorption performances of CS600 and CS600-MgCl
2
to Pb
2+
in aqueous solutions. All the experiments were carried out at pH of 7. According to the Freundlich–Langmuir model, CS600-MgCl
2
had a higher adsorption capacity (152.3 mg/g) than CS600 (134.3 mg/g). FTIR, SEM, XRD, BET, and ICP analyses were applied to inform the interpretation of the mechanism. CS600 was calcium-rich and mainly removed Pb
2+
through the ion exchange mechanism by replacing Ca
2+
in the biochar. The increased Pb
2+
adsorption capacity of CS600-MgCl
2
was mainly due to the enlarged specific surface area and the formation of Mg
3
(OH)
5
Cl·4H
2
O on the modified biochar. Findings of this study suggest that both CS600 and CS600-MgCl
2
can be used to remove heavy metal ions from wastewater and MgCl
2
can improve the sorption performance of biochar.
C-type lectins, one of the pattern recognition receptors (PRRs), play significant roles in innate immune responses through binding to the pathogen-associated molecular patterns (PAMPs) presented on ...surfaces of microorganisms. Here, a novel C-type lectin (named as MaCTL) from blunt snout bream (Megalobrama amblycephala) was cloned and characterized. The open reading frame (ORF) of MaCTL is 573 bp long encoding a putative protein of 190 amino acids (aa), which contains a typical feature of signal peptide at 1–23 aa, a characteristic CRD domain at 45–178 aa and a WND/EPN motif that is required for carbohydrates-binding specificity. Phylogenetic analysis indicated that MaCTL is a novel member of CTL family and possessed the highest similarity to that of grass carp (92.11%). The qRT-PCR analysis revealed that MaCTL expressed widely in all examined normal tissues, including heart, liver, spleen, kidney, head-kidney, gill, intestine and muscle, with the higher expression in the spleen, liver and muscle. The expression of MaCTL in spleen was significantly elevated, peaking at 9 h and 6 h after LPS stimulation and Aeromonas hydrophila challenge, respectively, suggesting its association with involvement in innate immune response. The recombinant MaCTL protein (rMaCTL) agglutinated markedly both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria, including Escherichia coli, Vibrio anguillarum, Vibrio vulnificus and Aeromonas hydrophila, in a Ca2+-dependent manner. Meanwhile, rMaCTL showed the binding effects on the five bacteria and four carbohydrates, such as glucose, surose, LPS and PGN. Moreover, rMaCTL could remarkably inhibit the growth of three types of bacteria in vitro. Overall, the results obtained above demonstrated firmly that MaCTL binds to carbohydrates on the surface of diverse pathogens as a PRR and elicits antimicrobial responses, which shed new light on a better understanding of antibacterial functions of CTLs in teleost fish.
•A novel C-type lectin from blunt snout bream was identified and characterized.•MaCTL expression were significantly upregulated after immune stimulation.•rMaCTL agglutinated various bacteria in vitro in the presence of Ca2+.•rMaCTL bound distinct bacteria and some carbohydrates such as LPS and PGN.•rMaCTL exhibited antimicrobial activity by inhibiting the growth of bacteria.
As an economically important fish,
Opsariichthys bidens
has obvious sexual dimorphism and strong reproductive capacity, but no epigenetics study can well explain its phenotypic variations. In recent ...years, many microRNAs involved in the regulation of reproductive development have been explored. In this study, the small RNA libraries of
O. bidens
on the testis and ovary were constructed and sequenced. A total of 295 known miRNAs were obtained and 100 novel miRNAs were predicted. By comparing testis and ovary libraries, 115 differentially expressed (DE) miRNAs were selected, of which 53 were up-regulated and 62 were down-regulated. A total of 64 GO items (padj < 0.01) and 206 KEGG pathways (padj < 0.01) were enriched in the target gene of miRNA. After that, the expression levels of nine DE miRNAs, including let-7a, miR-146b, miR-18c, miR-202-5p, miR-135c, miR-9-5p, miR-34c-3p, miR-460-5p and miR-338 were verified by qRT-PCR. Furthermore, bidirectional prediction of DE miRNAs and sex-related genes was carried out and the targeting correlation between miR-9-5p and
nanos1
was verified by Dual-Luciferase reporter assay. Our findings identified the differentially expressed miRNA and paved the way to new possibilities for the follow-up study on the mechanism of miRNA-mRNA interaction in the gonads of
O. bidens
.
MicroRNAs (miRNAs) play vital roles in diverse biological processes, including in immune response. Blunt snout bream (Megalobrama amblycephala) is a prevalent and important commercial endemic ...freshwater fish species in China's intensive polyculture systems. To identify immune-related miRNAs of M. amblycephala, two small RNA (sRNA) libraries from immune tissues with or without lipopolysaccharide (LPS) stimulation were constructed and sequenced using the high-throughput sequencing technology. Totally, 16,425,543 and 15,076,813 raw reads, corresponding to 14,156,755 and 13,445,869 clean reads, were obtained in the normal and infected libraries, respectively. A total of 324 miRNAs, including 218 known miRNAs and 106 putative novel miRNAs were identified by bioinformatic analysis. We analyzed differentially expressed miRNAs between two libraries using pairwise comparison. 113 (34.88%) miRNAs were found to be significantly differentially expressed between two libraries, with 63 (55.75%) exhibiting elevated expression in LPS stimulation sample. Thereinto, a number of known miRNAs were identified immune-related. Real-time quantitative PCR (RT-qPCR) were implemented for 12 miRNAs of two samples, and agreement was confirmed between the sequencing and RT-qPCR data. Target genes likely regulated by these differentially expressed miRNAs were predicted using computational prediction. The functional annotation of target genes by Gene Ontology enrichment (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analysis (KEGG) indicated that a majority of differential miRNAs might involved in immune response. To our knowledge, this is the first comprehensive study of miRNAs in response to LPS stimulation in M. amblycephala, even in fish. These results deepened our understanding of the role of miRNAs in the intricate host's immune system, and should be useful to develop new control strategies for host immune defense against various bacterial invasions in M. amblycephala.
•Two sRNA libraries were constructed and sequenced with or without LPS infection.•A total of 218 conserved miRNAs and 106 putative novel miRNAs were identified.•113 miRNAs were found to be differentially expressed between two libraries.•Selected miRNA expression profiles were consistent between sequencing and RT-qPCR data.•This is the first comprehensive study of miRNAs for immune tissues in Megalobrama amblycephala.
Hybridization is a common breeding technique that can improve germplasm through heterosis in aquaculture. However, the regulation of key gene expression, including the details of transcriptional ...level changes at the beginning of hybridization events, remains largely undefined, especially in teleosts. In this study, by interspecies crossing between two pure lines of Nile tilapia and blue tilapia, we obtained a hybrid tilapia population as a model to elucidate heterosis, and we traced the molecular outcomes of growth hormone (GH) expression and allele-specific expression (ASE) in hybrids. The hybrids display growth vigor compared to their parents in the 120-day growth trial. GH mRNA expression was uniquely expressed in the pituitary. Higher GH expression was found in the hybrid than the midparent value, in both males and females, showing a nonadditive pattern. We identified four single-nucleotide polymorphism sites between Nile tilapia and blue tilapia. Subsequently, by pyrosequencing, we found asymmetric allelic expression in hybrids with higher maternal allelic transcript ratios in both males and females. Fasting significantly increased GH expression in hybrids, but asymmetric allelic expression was not affected by feeding or fasting conditions. Finally, we identified
cis
and
trans
effects
via
overall expression and ASE values in the hybrid, which showed that the
cis
and
trans
effects promoted the expression of maternal subgenome in the hybrid, contributing to the expression superiority of GH in hybrid tilapia. Taken together, the results of our study first illustrated the concept of GH expression superiority and its formation mechanism in hybrid fish with growth vigor.
Lipopolysaccharide induced TNFα factor (LITAF) is an important transcription factor responsible for regulation of tumor necrosis factor α. In this study, a novel
gene (designated as
) was identified ...and characterized from blunt snout bream,
The full-length cDNA of
was of 956 bp, encoding a polypeptide of 161 amino acids with high similarity to other known LITAFs. A phylogenetic tree also showed that
significantly clustered with those of other teleost, indicating that
was a new member of fish LITAF family. The putative maLITAF protein possessed a highly conserved LITAF domain with two CXXC motifs. The mRNA transcripts of
were detected in all examined tissues of healthy
.
, including kidney, head kidney, muscle, liver, spleen, gill, and heart, and with the highest expression in immune organs: spleen and head kidney. The expression level of
in spleen was rapidly up-regulated and peaked (1.29-fold,
< 0.05) at 2 h after lipopolysaccharide (LPS) stimulation. Followed the stimulation of
,
transcriptional level was also transiently induced to a high level (51.74-fold,
< 0.001) at 4 h after LPS stimulation. Taken together, we have identified a putative fish LITAF ortholog, which was a constitutive and inducible immune response gene involved in
.
innate immunity during the course of a pathogenic infection.
Cadmium (Cd) pollution is regarded as a disturbing environmental problem due to its serious risks to the water body and human health. The removal of cadmium from wastewater is thus crucial to avoid ...its harmful effects on the ecosystem. This study comprehensively investigated Cd(II) adsorption onto MgCl2 modified biochar (MgC600) and results showed that the adsorption capacity of MgC600 was more than twice of that of pristine biochar due to its enhanced ion exchange ability. Response surface analysis revealed that reaction time played a crucial role in the Cd(II) adsorption, followed by initial concentration and solution pH. Moreover, the optimal adsorption conditions and capacity were precisely given by the quadratic regression model and thus proved that the model can be applied to predict the operation conditions of Cd(II) adsorption. Finally, a new model defined as BJP model (CtC0=11+(KJ⋅t)P) was proposed and proved to be more suitable for the fixed bed filtration process. Overall, our findings provide a promising material in treatment of Cd(II)-rich wastewater and give a clear picture of its application. More importantly, the newly developed BJP model can accurately describe the fixed bed filtration process and further promote its application in wastewater treatment.
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•Cd(II) adsorption capacity of MgC600 (72.1 mg/g) was twice more than that of C600 (32.0 mg/g).•The order of importance of factors affecting the Cd(II) adsorption were: t > C0 > pH.•The quadratic regression model could accurately predict the optimal conditions of Cd(Ⅱ) adsorption.•A more accurate and simple model (CtC0=11+(KJ⋅t)P) for fixed bed filtration was proposed.
Parachromis managuensis is a native cichlid fish from Central America that has been recently introduced to Southern China. The present study aimed to identify the adaptive evolution of P. managuensis ...using transcriptome data and provided genetic information regarding this novel fish in China. We obtained the transcriptome sequences from a mixed cDNA library of P. managuensis. A total of 19,419,739 raw reads were obtained from the cDNA library. The de novo assembly generated a total of 102,977 unigenes. The genomic data of Atlantic cod (Gadus morhua) and Nile tilapia (Oreochromis niloticus) were used to identify orthologs by phylogenetic analysis. Based on the phylogeny, we detected 105 positively selected genes in P. managuensis from 6197 orthologous unigenes. The GO annotation revealed that the T-box protein 20 (TBX20) in the category 'Immune system process' was positively selected and four positively selected genes were found in the 'Immune system' pathway by KEGG analysis. Among them, the genes encoding for phosphoinositide 3-kinase adapter protein 1, ras-related protein Rap-1b, complement factor I and probable ATP-dependent RNA helicase DHX58 were associated with immune adaptation. These findings can provide additional information regarding the natural selection of P. managuensis and can be used as a representative example for future comparative transcriptome and immunological studies.
It has been shown that piRNA is the largest class of small non-coding RNA in germline cells of animals which plays key roles in transposons regulation and transcriptional activities. In the present ...study, piRNAs from two small RNA libraries including ovary and testis of Nile tilapia were identified and characterized. By length and k-mer based small RNA prediction algorithm, 279,059 and 583,230 small RNA reads were confirmed as piRNA from ovary and testis, respectively. The identified piRNAs showed evolutionarily conserved characterization, such as uridine bias in the 5′ ends. The 142,961 and 296,775 piRNAs from ovary and testis were mapped to the draft assembly of the tilapia genome, respectively. Both ovary and testis piRNAs were enriched from linkage (LG)6 and LG7. Meanwhile, the even distribution of +strand and −strand suggested the Ping–pong pathway (a double-displacement reaction of +strand and −strand) hypothesis. These piRNAs were derived from the upstream −2 kb and downstream +2 kb as well as gene regions which suggested a regulatory function on transcription activities. In gene regions, abundant piRNAs were derived from 5′UTR, 3′UTR and CDS. Furthermore, we characterized the differentially expressed piRNAs between ovary and testis. In total, 1979 and 2453 piRNAs were significantly higher and lower expressed in ovary compared to that in testis, respectively. Thereinto, the most concentrated up-regulate and down-regulate piRNAs were both from serine/threonine–protein kinase PIM genes of different transcripts. These findings will be helpful to facilitate studies on the piRNAs regulation on genes during gonad development of teleosts.
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